Jaw Movements Research Articles

Sensory Texture and Mastication Physics of Multi-Phase Meat Products

Food products often consist of several phases. Comminuted meat products, for example, are multiphase systems consisting of structured meat particles and unstructured batter-like substance. To develop and understand the processing of these products, it is important to understand the sensory and mechanical perception principles. To this end, two-phase food prototypes consisting of mixtures of ground beef and beef batter were prepared and subjected to sensory, texture, and oral processing analysis. The oral processing analysis focused on the biomechanical data of the chewing process, namely the kinematics of jaw movement and electromyographic activity. The ground meat served as the anisotropic phase and the meat dough as the isotropic phase. A significant increase in muscle activity, duration per bite, and occlusion time with increasing proportion of fibrous particles was demonstrated (p < 0.05). In contrast, a higher proportion of isotropic substance resulted in significantly higher amplitudes of jaw movement and faster jaw kinetics (p < 0.05). In mixed regimes, the system responded mainly according to the dominant phase, with sensory or mechanical response changing at a critical point. In combination with texture and sensory data, a holistic characterization of the food models could be performed.

Intra-articular platelet-rich plasma injection versus hydrocortisone with local anesthetic injections for temporo mandibular disorders.

Disorders of temporomandibular joint (TMDs) are characterised by a variety of symptoms, including discomfort in the orofacial region, muscle tenderness, restricted jaw motion and noise at the joint. Additional neurological symptoms such as headaches, vertigo, heaviness, and altered vision may also coexist with TMDs. Because prostaglandin production is a critical mediator of inflammatory reaction and is inhibited by corticosteroids, they have anti-inflammatory effects. Platelet rich plasma popularly considered as PRP is a concentration of platelets and related growth factors that may have therapeutic effects by attracting, promoting, and differentiating cells as well as redesigning tissue. 64 joints totaling 40 individuals with temporomandibular joint problems were split into two categories (Category A and Category B). PRP was applied to category A's (36 joints of 20 patients) joints, while Group B's joints received hydrocortisone combined with local anaesthetic (28 joints of 20 patients). Patients were evaluated for tenderness, , maximum inter incisal opening (MIO) and clicking sound at TMJ prior to and following treatment at intervals of one week, one month and 6 months of the first week and third month. When there was comparison of outcomes in study participants receiving injections of platelet rich plasma and study participants receiving injections of hydrocortisone with local anesthetic then it was found that although both type of study participants got reduction in pain, increased opening of mouth and reduction in clicking sound however the difference between two groups was not significant statistically. There was no statistically significant difference between injections of platelet rich plasma and hydrocortisone with local anesthetic solution regarding outcomes in disorders of temporomandibular joint, however the results were slightly better in study participants receiving platelet rich plasma injections. This study demonstrated that while treating patients with TMJ issues, local anaesthesia combined with hydrocortisone as well as intra-articular injection of PRP help in reduction in pain, increase mouth opening, and minimize joint sound. Additionally, it was discovered that intra-articular injection of PRP was more successful in treating patients in this trial than local anaesthetic combined with hydrocortisone.

Marin-Amat Syndrome: More Than Meets the Eye.

A 52-year-old man complained of right eye closure whenever eating. He had experienced a right-sided Bell's palsy approximately before 12 months. An examination showed unilateral eye closure on jaw opening or lateral jaw movements, related to active contraction of the entire orbicularis oculi muscle, in addition to ipsilateral hemifacial spasm (Video 1). Marin-Amat syndrome is an acquired synkinesis occurring most frequently after Bell's palsy and is the opposite of the more common Marcus Gunn phenomenon, in which there is eyelid retraction on jaw opening or horizontal movement. It is sometimes erroneously termed an “inverse” Marcus Gunn, although this is a congenital condition in which there is inhibition, and resulting ptosis, of the levator palpebrae muscle on mouth opening, rather than the active contraction of orbicularis oculi seen in Marin-Amat syndrome. Botulinum toxin to the orbicularis oculi muscle, otherwise generally ineffective in the Marcus Gunn phenomenon, can therefore be therapeutic.

Assessment of Patient-Centered Outcomes When Treating Palatally Impacted Canines Using Conventional Versus Accelerated Minimally Invasive Corticotomy-Assisted Orthodontic Treatment: A Randomized Controlled Trial.

ObjectiveThis study aimed to investigate whether there were any differences in pain levels, discomfort, and functional impairments when treating palatally impacted canines (PICs) using the conventional treatment method compared to the accelerated minimally invasive corticotomy-assisted method.Materials and methodsFifty-two patients (11 males and 41 females) with unilateral PICs were included. The patients were randomly assigned to the conventional traction group (26 patients, mean age of 20.37 ± 2.15 years) or the minimally-invasive corticotomy-assisted group (26 patients, mean age of 20.18 ± 2.18 years). The levels of pain, discomfort, and functional difficulties were assessed using a visual analog scale (VAS) after 24 hours (T1), four days (T2), seven days (T3), 14 days (T4), and 28 days (T5) following the surgical exposure procedure.ResultsThere were no statistically significant differences between the two treatment groups for any patient-centered outcome at all assessment times (P>0.01). The levels of pain and discomfort were slightly greater in the conventional group than in the corticotomy-assisted group on the first day after surgical exposure, with no significant difference between the two groups (mean pain: 4.11, P=0.481; mean discomfort: 9.00, P=0.223). Pain and discomfort required seven days to reach low levels and four weeks to reach the lowest levels in both study groups. The levels of swelling, mastication difficulties, swallowing difficulties, limitation in jaw movements and speech changes were mild to moderate on the first postoperative day and the recovery time was four days postoperatively for swallowing difficulties and speech changes. In comparison, the recovery time was seven days for the other three outcomes in both study groups.ConclusionsAfter one day of the surgical intervention, either by conventional or corticotomy-assisted methods, the patients reported mild to moderate pain, discomfort, and functional impairments. These disabilities gradually reached low levels during the first and second weeks to reach their lowest levels four weeks postoperatively in both study groups. The similarity between the conventional and the acceleration methods in pain levels and other oral disabilities may make corticotomy-assisted treatment a comfortable and effective method when treating adult patients with PICs. In addition, patient satisfaction with the corticotomy-assisted procedure was high.

Topical review- salivary biomarkers in chronic muscle pain.

Muscle related temporomandibular disorders (myogenous TMD), one of the most common orofacial pain conditions, is characterized by facial pain and often accompanied by jaw movement limitations. Although the underlying biological mechanisms are still unclear, a cluster of proteins and peptides is assumed tobe involved in the pathophysiology. These proteins andpeptides may be measured in a simple non-invasive saliva sample. This work investigated whether saliva can be used to sample algogenic substances that can serve asmolecular biomarkers for TMD myalgia. Saliva and blood samples were collected from healthy individuals (n=69) and patients diagnosed with TMD myalgia (n=39) according to the Diagnostic Criteria for TMD. Unstimulated and stimulated whole, parotid, and sublingual saliva were analysed. The protein profiles were investigated using two-dimensional gel electrophoresis followed by identification with liquid chromatography tandem mass spectrometry. Levels of nerve growth factor (NGF), calcitonin gene-related peptide (CGRP), and brain derived neuro-tropic factor (BDNF) were determined using western blotting based technology and multiplex electro-chemiluminescence assay panel. Glutamate, serotonin, and substance p (SP) were determined using commercially available methods. Different saliva collection approaches resulted insignificant differences in the protein profile as well as inthe expression of NGF, BDNF, CGRP, SP, and glutamate. Stimulated whole saliva showed least variability in protein concentration (35%) and was correlated to plasma levels ofglutamate. Unlike SP and glutamate, NGF and BDNF expressed a rhythmic variation in salivary expression withhigher levels in the morning (p<0.05). Patients with a diagnosis of TMD myalgia had significantly higher levels of salivary glutamate but lower salivary NGF and BDNF compared to controls; in addition, the lower NGF and BDNF levels correlated to psychological dysfunction. Thequantitative proteomics data revealed 20 proteins that were significantly altered in patients compared to controls. The identified proteins are involved in metabolic processes, immune response, and stress response. Dissimilarities in protein profile and clinical variables were observed between TMD myalgia and myofascial pain. The work highlights the importance of consistency in saliva collection approaches, including thetiming of the collection. It displayed significant changes in pain specific mediators and protein profile in TMD myalgia and furthermore dissimilarities between subclasses indicating different pathophysiology. After extensive validation, potential salivary biomarkers can becombined with clinical features to better understand and diagnose TMD myalgia.

An investigation of interference between electromagnetic articulography and electroglottography

The present study tested whether there is cross interference between state-of-the-art electromagnetic articulography (EMA) and electroglottography (EGG) during the acquisition of kinematic speech data. In Experiment 1, we calibrated EMA sensors with and without EGG electrodes present in the EMA field. In Experiment 2, EMA was used to record lip, tongue, and jaw movements for one male talker and one female talker, with and without simultaneous EGG recording. Collectively, the results provide no evidence of signal artifacts in either direction, suggesting that current EMA and EGG technology can be combined to reliably assess laryngeal and supralaryngeal motor coordination in speech.

A rare case of unilateral psoriatic arthritis of the left temporomandibular joint: MRI and CBCT findings

Psoriatic arthritis (PsA) of the temporomandibular joint (TMJ) is a rare type of inflammatory arthritis. We present a 21-year-old male diagnosed with psoriasis six years ago. Inflammatory autoimmune arthritis was diagnosed. TMJ involvement comprised arthralgia, degenerative joint disease, joint pain, limited range of jaw movements, and crepitus. Biomarkers revealed a C-reactive protein of 0.14 mg/L and seronegative inflammation with negative rheumatoid factor. At imaging important left condyle morphology derangements with erosions, decreased subchondral bone fat signal, condyle edema, osteophytes, and periosteal apposition, and loss of the normal disk position and morphology were present. The particularity of this case is given by the rapid onset of psoriasis arthritis with negative rheumatoid factor in a young male and juxta-articular new bone formation. The treatment plan comprised anti-inflammatory drugs, methotrexate, and folic acid, aimed for the general disease, and an occlusal splint, aiming for the relief of the TMJ symptoms.

31EMF Intubatable 3D Printed Airway Manikin: A Feasibility Study for Replicating Real Patient Anatomy

31EMF Intubatable 3D Printed Airway Manikin: A Feasibility Study for Replicating Real Patient Anatomy

Premolar Extraction Affects Mandibular Kinematics.

The practice of premolar extraction in orthodontics is controversial for its potential detrimental effects on the stomatognathic system. However, the ways in which premolar extraction affects mandibular function are still poorly understood. The purpose of this study was to assess the influence of premolar extraction on mandibular kinematics by evaluating axiographic tracings. Forty-five orthodontically treated patients with premolar teeth extraction were compared with 45 paired untreated controls, selected for the absence of malocclusions. Systematic three-dimensional axiographic recordings of the mandibular movements were performed for protrusive-retrusive movements and speech. The transversal deviations and length of the movements were recorded for both sides along with the rotation angle during speech. Differences between the axiographic variables were analyzed via the permutation test and Wilcoxon rank-sum test. Linear regression was performed to test whether axiographic parameters were predictive of group affiliation. Dot plots were used to explore the distribution of each of the axiographic outcomes, and isometric principal component analysis to assess the differences between the cumulative effects of premolar extraction on jaw motion. The mandibular lateral translation in protrusion-retrusion and speech, the amount of rotation as well as the length of mandibular movements during speech were significantly higher in the treated subjects than in the controls, while retral stability did not differ. The linear regression yielded significant results for the mandibular lateral translation in protrusion-retrusion. The isometric principal component analysis showed higher values of the axiographic variables for 11 out of 45 individuals in the study sample compared with the control group. Premolar extraction altered mandibular kinematics in at least 25% of the cases within our sample, and the transversal discrepancy between protrusive and retrusive tracings was even predictive of group affiliation. These results support the notion that the routine practice of premolar extraction as part of the orthodontic treatment should be discouraged. It is compelling to perform further studies to assess whether a disrupted kinematics of the mandible is associated to temporomandibular disorders.

Use of Automated Kinematic Diadochokinesis Analysis to Identify Potential Indicators of Speech Motor Involvement in Children With Cerebral Palsy.

This study examined multiple variables obtained from an automated measure of lip movement during a diadochokinesis (DDK) task to identify those with potential to detect mild speech motor involvement in school-age children diagnosed with cerebral palsy (CP). Eight children with CP and high speech intelligibility and a matched group of eight children with typical development (TD) completed a DDK task while their lip and jaw movements were recorded. A custom MATLAB algorithm was used to automatically extract 23 kinematic measures of children's lip movements during production of the DDK sequences. Mann-Whitney U tests were used to compare groups on the kinematic measures, and receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of measures that significantly differed between groups. Five of the 23 kinematic variables differed significantly between the CP and TD groups. These were two measures of overall DDK performance (i.e., duration of the DDK sequence and number of cycles) and three spatial and temporal measures of lip movement. Duration of the DDK sequence and the mean displacement of the lips across cycles had the highest diagnostic accuracy, differentiating CP and TD groups with 88% sensitivity and 88% specificity. Automatically derived kinematic measures of DDK sequences differentiated children with CP and high intelligibility from typically developing children. Future research is needed to determine the clinical utility of these measures for detecting speech motor impairment.

Orofacial pain and dysfunction in patients with Parkinson's disease: A scoping review.

Parkinson's disease (PD) is commonly known as a disorder that affects the smooth performance of body movements. In addition to the motor impairments, patients with PD often experience pain. Both motor impairments and pain can occur throughout the body, hence including the orofacial region. However, currently, there is a lack of knowledge on the orofacial manifestations. Since orofacial pain and dysfunction can, amongst others, reduce the quality of life of patients with PD, it is important to explore the prevalence of these symptoms in the PD population. To provide a broad overview of the relevant literature on orofacial pain and dysfunction in patients with PD. Furthermore, we aim to generate hypotheses for future research on this topic. A literature search (in PubMed, Embase.com, Web of Science [Core collection], and Cochrane Library) was performed on 20 January 2022, in collaboration with a medical librarian. In total, 7180 articles were found, of which 50 were finally included in this scoping review. In the included studies, pain (e.g. orofacial pain (N= 2) and temporomandibular disorder pain (N= 2)), orofacial motor dysfunction (e.g. limited jaw movements (N= 10), reduced maximum muscle output (N= 3), chewing difficulties (N= 9), unspecified TMD (N= 3), sensory disturbances (N= 1)), and bruxism (N= 3) were observed more often in patients with PD than in healthy controls. Patients with PD experience more pain in the orofacial area and more dysfunction of the masticatory system than their healthy peers. This scoping review can increase health care providers' awareness of the problems that can be encountered in the orofacial area of PD patients, especially pain syndromes also occur in the orofacial region and not only in the extremities. Besides, dysfunction of the orofacial area is elaborated in this scoping review, which helps to understand that this limits PD patients' quality of life. Further, the outcomes of this scoping review can assist in encouraging collaboration between medicine and dentistry. Finally, this scoping review suggests new research areas, based on the gaps identified in the current literature on this topic. Ultimately, this will improve individualized strategies for reducing orofacial pain and/or dysfunction in PD patients.

MuteIt

In this paper, we present MuteIt, an ear-worn system for recognizing unvoiced human commands. MuteIt presents an intuitive alternative to voice-based interactions that can be unreliable in noisy environments, disruptive to those around us, and compromise our privacy. We propose a twin-IMU set up to track the user's jaw motion and cancel motion artifacts caused by head and body movements. MuteIt processes jaw motion during word articulation to break each word signal into its constituent syllables, and further each syllable into phonemes (vowels, visemes, and plosives). Recognizing unvoiced commands by only tracking jaw motion is challenging. As a secondary articulator, jaw motion is not distinctive enough for unvoiced speech recognition. MuteIt combines IMU data with the anatomy of jaw movement as well as principles from linguistics, to model the task of word recognition as an estimation problem. Rather than employing machine learning to train a word classifier, we reconstruct each word as a sequence of phonemes using a bi-directional particle filter, enabling the system to be easily scaled to a large set of words. We validate MuteIt for 20 subjects with diverse speech accents to recognize 100 common command words. MuteIt achieves a mean word recognition accuracy of 94.8% in noise-free conditions. When compared with common voice assistants, MuteIt outperforms them in noisy acoustic environments, achieving higher than 90% recognition accuracy. Even in the presence of motion artifacts, such as head movement, walking, and riding in a moving vehicle, MuteIt achieves mean word recognition accuracy of 91% over all scenarios.

Congenital Mandibular Hypoplasia: Patient-Specific Total Joint Replacement as a Line Extension in the Treatment of Complex Craniofacial Anomalies

IntroductionCongenital mandibular hypoplasia (CMH) remains challenging because of the underlying combined hard and soft tissue deficiency. Treatment options include craniofacial distraction, orthognathic surgery, and autologous grafts, although the latter produces inadequate results after distraction and autologous grafting. Unsatisfactory long-term stability may cause relapse, necessitating reoperation.Material and MethodsWe investigated the feasibility of using alloplastic total joint replacement (TJR) in growing and young adult CMH patients. The primary outcome was long-term reconstruction stability, without implant failure. Secondary outcomes were TMJ function and pain, and jaw movements achieved during surgery.ResultsThree patients (age: 9–22 years) were treated by the same surgeon at one institution during 2018–2021. Anamnesis and clinical parameters were obtained from patient records. Preoperative 3D-scans were superimposed with postoperative 3D-scans and preoperative plans, including TJR-implant STL files, to measure jaw movement. All patients underwent prior reconstructive surgery. Mandibular movement of 16.4–20.1 mm in the sagittal direction was achieved. Post-TJR follow-up ranged from 24 to 42 months. No long-term complications occurred. At the latest follow-up, the maximal interincisal opening was between 21 and 40 mm, and all implants were functioning, without failure.ConclusionIn selected CMH cases, alloplastic TJR can deliver satisfactory medium-term results with predictable and stable outcomes, even in growing patients.

An investigation of interference between electromagnetic articulography and electroglottography.

The present study tested whether there is cross-interference between electromagnetic articulography (EMA) and electroglottography (EGG) during the acquisition of kinematic speech data. In experiments 1A and 1B, EMA sensors were calibrated with and without EGG electrodes present in the EMA field. In experiment 2, EMA was used to record lip, tongue, and jaw movements for one male speaker and one female speaker, with and without simultaneous EGG recording. Collectively, the results provide no evidence of signal artifacts in either direction, suggesting that EMA and EGG technology can be combined to reliably assess laryngeal and supralaryngeal motor coordination in speech.

Evaluation of Patient Comfort and Impact of Different Anesthesia Techniques on the Temporomandibular Joint Arthrocentesis Applications by Comparing Gow-Gates Mandibular Block Anesthesia with Auriculotemporal Nerve Block.

Aim Temporomandibular disorders (TMDs) are clinical situations that are characterized by pain, sound, and irregular movements of the temporomandibular joints. The most common method in the treatment of TMDs is arthrocentesis. This study aims to compare the effect of conventional extraoral auriculotemporal nerve block (ANB) and Gow-Gates (GG) mandibular anesthesia techniques on patient comfort in an arthrocentesis procedure. Materials and Methods We performed this study on 40 patients who underwent TMJ arthrocentesis with ANB (n = 20) or GG (n = 20) mandibular anesthesia techniques at the Marmara University Faculty of Dentistry between 2016 and 2019. The predictor variable was the type of an anesthesia technique, and the outcome variables included were pain, maximum mouth opening (MMO), and protrusive movement (PM). They were compared at the preoperative period and 3rd and 6th month periods. Statistical analysis included means with standard deviations, a one-way ANOVA for continuous data, and the results were evaluated at the significance level of p < 0.05. Results No statistically significant difference was observed between the VAS values, MMO, and PM averages of preoperative, 3rd and 6th months of ANB and GG (p=0.142, p=0.209, and p=0.148). Conclusion Both anesthesia techniques have provided effective results in terms of pain and functional jaw movements in the postoperative period in arthrocentesis treatment.

Protective effect of pantothenic acid in kainic acid-induced status eilepticus and associated neurodegeneration in mice

Pantothenic acid (PA) is a water-soluble vitamin (Vitamin B) that has recently been investigated in various chemical-induced neurotoxicity studies. The present study was designed to explore the biological importance of PA as a neuromodulator by releasing monoamine oxidase (MAO)-A and MAO-B in kainic acid (KA)-induced status epilepticus and the associated neurodegeneration in mice. The mice were intraperitoneally administered with KA at a dose of 10 mg/kg, and the injection solution was maintained at pH 7.2 ± 0.1 before the injection. Subsequently, the mice were observed for various behavioral changes, such as grooming, rearing, hind limb scratching, urination, defecation, jaw movements, salivation, head nodding, incidence of convulsions, and their latency or any mortality, which were recorded during a 4-h period. Further, the animals were euthanized for biochemical and histopathological analysis. The oxidative stress status was determined by measuring levels of glutathione, superoxide dismutase, nitrites, and catalase enzymes. The MAO-A and MAO-B activities, which represent an indicator of brain memory function, and the level of tumor necrosis factor alpha, which is an inflammatory marker in brain tissues, were also measured. The PA pre-treated mice showed a significant increase in retention with latency, as demonstrated in the passive avoidance test, which indicate its protective effect against the KA-induced cognitive deficit. The results showed that the anti-oxidative and anti-inflammatory potential of PA is due to the change in lipid peroxidation, which may prevent mitochondrial damage in neuronal cell, thereby conferring neuroprotection.

Diagnosis and Treatment of Temporomandibular Arthrosis: a Clinical Case

Background. Complexity of anatomical structure, diversity of clinical pattern, lack of a unified theory of etiology, pathogenesis and treatment of this pathology, individual aspects of the course of the disease complicate the diagnosis and choice of relevant treatment for patients with various nosological forms of the temporomandibular joint diseases.Clinical case description. Patient P., 32 years-old, went to the clinic of orthopaedic dentistry with complaints of noise phenomena in the temporomandibular joint (clicks in the joint area have been registered for five years, the noise increased six months ago), dental crowding, absence of tooth 3.5. The patient underwent clinical examination with creating diagnostic models, electromyography of the masticatory muscles, axiography, computed tomography and MRI of the temporomandibular joint. Through computed magnetic resonance imaging of the temporomandibular joint, electromyography and axiography the patient was accurately diagnosed with deforming arthrosis of the temporomandibular joint complicated by dislocation of the intra-articular disc. A therapeutic-diagnostic plastic milled splint on the mandible was implemented. Dynamic observation during treatment was carried out. The effect of the treatment was observed after three months. The control cone-beam computed tomography of the temporomandibular joint showed positive dynamics in the form of an even expansion of all regions of the joint cavity on both sides, centered position of the heads of mandible in the mandibular fossa, but the cortical bone destruction of the upper contour of the mandibular head on the left was still present. After six months of treatment, electromyograms showed a decrease in bioelectrical activity at rest and an increase in bioelectrical activity during chewing on all the masticatory muscles within normal limits. The re-examination after six months revealed smoother vertical movements of the lower jaw, an increase in the amplitude of laterotrusion and protrusion, their symmetry, no “blockage” of lower jaw movements.Conclusion. An integrated application of radiologic imaging, electromyography and axiography in the diagnosis of temporomandibular joint diseases is crucial for objective analysis of the results, assessment of the quantitative and qualitative characteristics of the masticatory muscles and lower jaw movements, which ultimately determines the optimal patient surveillance and controlled treatment outcomes.

Got rhythm? Rhythmicity differences reflect different optimality criteria in feeding and locomotor systems.

Evolutionary analyses of joint kinematics and muscle mechanics suggest that, during cyclic behaviors, tetrapod feeding systems are optimized for precise application of forces over small displacements during chewing, whereas locomotor systems are more optimized for large and rapid joint excursions during walking and running. If this hypothesis is correct, then it stands to reason that other biomechanical variables in the feeding and locomotor systems should also reflect these divergent functions. We compared rhythmicity of cyclic jaw and limb movements in feeding and locomotor systems in 261 tetrapod species in a phylogenetic context. Accounting for potential confounding variables, our analyses reveal higher rhythmicity of cyclic movements of the limbs than of the jaw. Higher rhythmicity in the locomotor system corroborates a hypothesis of stronger optimization for energetic efficiency: deviation from the limbs' natural frequency results in greater variability of center of mass movements and limb inertial changes, and therefore more work by limb muscles. Relatively lower rhythmicity in the feeding system may be a consequence of the necessity to prevent tooth breakage and wear, the greater complexity of coordination with tongue movements, and/or a greater emphasis on energy storage in elastic elements rather than the kinetics of limb movement.

Therapy outcome measures in temporomandibular disorder: a scoping review

ObjectivesTherapy outcome measures (TOMs) in temporomandibular disorders (TMDs) have not been systematically evaluated. We systematically explored the main TOM assessment methods for TMD TOMs used in previous studies.DesignScoping review.Data sourcesAccording...

A Modified Hyrax-Type Expander Is Effective for Distal Bodily Movement of the Maxillary First Molar

Impaction and eruption disturbance of permanent teeth are frequently encountered in orthodontic practice. The canine teeth play an important role both functionally and esthetically. Eruption disturbance of a maxillary canine, if left untreated, can cause not only disturbed jaw movement and esthetic problems, but also root resorption of adjacent permanent teeth, and thus should be diagnosed and treated appropriately. In this report, we present a case of a patient with eruption disturbance of the maxillary left canine in which the maxillary left second molar was extracted and the maxillary left first molar was distally moved with a Hyrax-type expander (Veltri Monolateral Screw®; Leone, Firenze, Italy) designed to enable the distal movement of a unilateral first molar in order to create eruption space for the maxillary left canine, resulting in smooth distal molar movement and alignment of the left maxillary canine in the dental arch. Furthermore, the maxillary third molar was also aligned to achieve a good occlusal relationship without reducing the number of teeth.